1. Field of the Invention
The present invention relates to an optical detecting device, and more particularly, to an optical detecting device capable of preventing light leakage.
2. Description of the Prior Art
Detection accuracy of the conventional optical detecting module is easily decreased due to light leakage. As the optical detecting module has low quality optical isolation, the detecting signal output by the light emitting unit may be directly transmitted to the light receiving unit before projecting onto an external object, so that the light receiving unit receives additional noise excluding the detecting signal, and quality of the optical signal is decreased to diminish the detection accuracy accordingly. As shown in FIGS. 7-8 of U.S. Pat. No. 8,888,701, the unit 102 is disposed close to the unit 103. Although the two units 715 are respectively utilized to drive the unit 102 to emit the detecting signal, and to guide the detecting signal reflected from the external object to be received by the unit 103, there has no isolation located between the unit 102 and the unit 103, and the unit 103 may receive parts of the detecting signal directly transmitted from the unit 102 without reflection by the external object. The leaked detecting signal does not have information about the external object, so that the detection accuracy of the optical detecting module is decreased while the leaked detecting signal and the reflected detecting signal are intermixed for receipt and analysis. Thus, design of an optical detecting module without light leakage is an important issue in the related industry.